Intestinal Microbiota

The Paper of the Month for June is from Gut Microbiome and is entitled 'Microbial gut dysbiosis induced by xenobiotics in model organisms and the relevance of experimental criteria: a minireview'  by Beatriz Yáñez-Rivera and Beatriz Ibarra-Mendoza.

The gastrointestinal tract harbors an astounding number of microbial cells, exceeding 10 trillion and encompassing around 3000 distinct species. These microorganisms shape dynamic communities that exhibit variations in density and structure throughout the digestive tract. The functions carried out by the gut microbiota are essential for the overall well-being of the hosts. However, the complex dynamics of the microbial communities are influenced by different factors. The disruption of the structure and function of microbial communities is called dysbiosis, which can occur either temporarily or permanently. Experimental studies use animal models such as mice, zebrafish, and invertebrates to comprehend their regulation. These studies have provided evidence that chemical residues in food items can disrupt the balance in the microbiota, thereby impacting the host's health. For instance, when orally exposed to hydrocarbons and pesticides, the abundance of lactic acid bacteria may be altered, potentially leading to inflammatory conditions in the intestine.

Another example is exposure to arsenic and manganese, which can affect specific microbiota members, such as Firmicutes. A great abundance of this bacteria group has been related to weight gain. The exposure to manganese produces changes in a sex-dependent manner, with increases in males and decreases in females. Additionally, it has been observed that exposure to pesticides in insects, such as bees, increases their susceptibility to opportunistic pathogens.

Still, there is a need to enhance our understanding to establish a comprehensive framework for identifying and quantifying secondary metabolites associated with host health. Additionally, several limitations are linked to experimental designs, such as sample collection methods (feces or gut dissection) and the detailed bioinformatic workflow for data analysis, which must be addressed to ensure homologation and repeatability between studies.

Thus, it is vital to foster a deeper understanding of the intricate relationship between the gut microbiota and the host to unravel the potential impact that pollutants may have on host health.

Beatriz Ibarra-Mendoza & Beatriz Yáñez-Rivera